The present invention relates to a device and a method by which two optical digital signals, identical in the number of constituent optical bit signals, are compared bit by bit without photo-electric conversion, and more particularly to an optical comparator and a method of comparing optical signals which utilize the Bragg diffraction of light by a surface acoustic wave.
With remarkable progress in light application techniques in recent years, there is a growing demand for various optical functional devices. Among other optical devices, optical comparators are basic devices for optical calculation, optical information processing, etc. Although greatly desired, such devices have not been actually implemented in practice.